Rubber mill



ay 14, 1968 JAMES T. MATSUOKA 3,382,529

RUBBER MILL Filed Jan. 5, 1967 FIG! ' INVENTOR FIG, 2 JAMES T. MATSUOKAUnited States Patent 3,382,529 RUBBER MILL James T. Matsuoka,Brecksville, Ohio, assignor, by mesnc assignments, to Stewart Bolling &Co., Inc., Cleveland, Ohio, a corporation of Ohio Continuation-impart ofapplication Ser. No. 575,005,

Aug. 25, 1966. This application Jan. 3, 1967, Ser.

4 Claims. (Cl. 18-2) ABSTRACT OF THE DISCLOSURE A mill, of the typecommonly referred to as a rubber mill, for processing plastic materialhaving a member extending across the operators side of the mill andmovably supported for interrupting the drive and stopping the mill uponmovement of the member towards the mill as by the operator approachingthe mill beyond a predetermined point.

This application is a continuation-in-part of my copending application,Ser. No. 575,005, filed Aug. 25, 1966, now abandoned.

In the operation of mills for processing plastic material of the typeknown as rubber mills, there is the possibility of serious injury to theoperators in the event their hands and arms, etc., are drawn into themill. Safety devices of various types have heretofore been proposed, forexample, a member located above the mill which when grabbed and pulledby the operator stops the :mill or a bar located in front of the milland below the operators knees which when pressed stops the mill, butthese devices have met with only limited success.

The present invention provides a novel and improved plastic mill of thetype referred to embodying safety features or devices which operateautomatically to stop the mill in the event the operator approaches themill beyond a predetermined position either intentionally oraccidentally, and which preferably includes means which prevents themill from being accidentally restarted.

Another object of the invention is the provision of a novel and improvedsafety device for attachment to or incorporation in a plastic processingmill of the character referred to which is simple and rugged inconstruction, reliable and automatic in operation and which will stopthe mill in the event the operator either intentionally or accidentallyapproach the mill beyond a predetermined position.

A more specific effect of the invention is the provision of apparatus ofthe character referred to which will prevent accidental restarting ofthe mill after having been stopped by operation of the safety device.

The invention resides in certain constructions and arrangements of partsand further objects and advantages of the invention will be apparentfrom the following description of the preferred embodiment describedwith reference to the accompanying drawings forming a part of thisspecification in which similar reference characters designatecorresponding parts, and in which:

FIG. 1 is a fragmentary front elevational view of a mill for processingplastic material embodying the present invention; and

FIG. 2 is a fragmentary sectional view approximately on the line 22 ofFIG. 1.

Plastic processing mills of the character here involved and commonlyreferred to as rubber mills comprise two heavy metal rolls driven bysuitable means usually an electric motor. The rolls are arrangedhorizontally with respect to one another with a slight spacetherebetween. The material to be processed is placed on the top of therolls and is worked or processed by the action of the rolls which arerotated in appropriate direction and at appropriate speeds as is wellunderstood in the art. The material being processed periodicallyrequires some manipulation or handling by the operator with the resultthat his hands, etc., may be drawn into the mills, that is, between therolls thereof.

The plastic processing mill shown in the drawing and designatedgenerally by the reference character A is not herein shown or describedin detail as it may be one of a number of such mills commerciallyavailable. Suffice it to say that the mill A comprises two processingrolls 10 and 11 rotatably supported in a suitable frame B comprising endmembers or housings 12 and 13. The mill A has incorporated in it theusual adjustments, etc., and is driven as by an electric motor, notshown, through a suitable speed reducer, etc.

The mill A includes safety apparatus designated generally as C forstopping the mill in the event the operator approaches the rolls eitheraccidentally or intentionally beyond a predetermined position. Thesafety apparatus C shown comprises a bar 20 extending across the frontof the roll 10 nearest to the operators position and on a level with orslightly above the plane of the axes of rotation of the processing rolls10 and 11. Opposite ends of the bar 20 are fixedly connected to andcarried by the ends of a downwardly projecting, normallyverticallypositioned arms 21 and 22 of bell crank levers 23 and 24pivotally connected at their elbows or the apexes of the angle formed bytheir arms as by stud shafts 26 and 27 to opposite ends of housingmembers 12 and 13 of the mill frame B. The bell crank levers 23 and 24are fixedly secured to reduced projecting ends of the stud shafts 26 and27 by nuts 30 and 31, respectively, and the stud shafts 26 and 27 aresupported for rotation about aligned axes in suitable brackets 32 and 33bolted to the end frame members 12 and 13, respectively.

The other arms of the bell crank levers extend at right angles to thearms 21 and 22 and project toward the rolls of the mill. Only the arm 35of the lever 23 clearly shows in the drawing, but the other lever has asimilar normally horizontal arm. Angular movement of the bell cranklevers is limited by stop pins 37 connected to the end housing 12 and 13and extending horizontally therefrom through holes 39 in the horizontalarms of the bell crank levers. The holes 39 are slightly larger than thepins 37 thus permitting limited angular movement of the bell cranklevers about the axes of the shafts or pins 26 and 27. In the embodimentshown the horizontal arm of the bell crank levers 23 and 24 are heavierthan the vertical arms and the construction including the location ofthe pins 37 and the holes 39 are such that the bell crank levers engageand ride or rest upon the top sides of the stop pins 37. In other Words,the location of the axes of rotation of the bell crank levers withrespect to the center of gravity of the assembly comprising the a levers23 and 24 and the bar 29 connected thereto is such that the assemblytends to rotate or is biased by gravity in a clockwise direction asviewed inPlG. 2.

Alternatively the levers may be spring biasedin the direcr tionmentioned.

If the operator approaches the rollsof the mill either accidentally orintentionally beyond a predetermined nected to the end housings lZand13by brackets M and 46, respectively. The switches 4a andZ. are inseries circuit with one another and when actuated operate electric,circuits which disconnect and plug the drive motor for the mill in theevent it is an alternating current motor;

f the drive motor is a direct current motor, the motor may bedynamically braked. Alternatively, a mechanical brake may be appliedupon the motor being disconnected or the drive for the mill may bethrougha disconnect clutch, in which event the switches could functionto disconnect the clutch and apply a mechanical brake to quickly stopthe mill. i

Each of the switches 40 and 42 is provided with or incorporates a manualreset, designated generally as 44 I incorporates or provides a built-indelay andprevents accidental restarting of the mill after beingstopped.For example, as by the operator being thrown or pulled against one ofthe switches. i

It is believed that it is obvious frorn the present disclosure that inthe event the hand of an operator inadvertently or otherwise becomesentangled in the material being processed and the operator therebypulled forward, that is, toward the rolls of the mill, he could almostinstantaneously engage the bar 2t} by his body, which bar is preferablyabout waist high, and themill would be stopped before he would beseriously injured, if injured at all. i i

From the foregoing description of the preferred embodiment of theinvention and alternative constructions,

itis believed that .it will be apparent that the objects heretoforeenumerated and others have been accomplished and that there has beenprovided a novel and improved mill for processing plasticmaterials, anda novel and improved safety device for such mills.

While the preferred embodiment has been described in considerable detailthe invention is not limited to the particular construction shownandreferred to, it being understood that the invention may be embodiedin other i apparatus and it is the intention to hereby cover alladapadjacent side of said side housings on the operator side of saidprocessing rolls, said lever-like members operating like bell cranklevers having one of their arms extending downwardly in a generallyvertical directionand the other of their arms extending in a generalhorizontal direction toward said processing rolls, a member extendingbetween said lever-like members and connected thereto below theirpivotal connections with said side housings, means limiting movement ofsaid lever-like members about their pivotal connections with said sidehousings, means biasing the assembly of said lever-like members and saidmembers connected therebetween in the direction to move said member awayfrom said processing rolls, and means actuated by movement of saidassembly in a direction opposite to its biased direction forinterrupting said drive means and quickly stopping rotation of saidprocessing rolls.

2. In a mill for processing plastic material 'having a frame includingspaced side housing in which a pair of processing rolls are supportedfor rotation about axes positioned generally horizontal with referenceto one another, power actuated drive means for rotating said processingrolls, and rneansfor quickly stopping rotation of the processing rollsuponinterruption of said drive means, a pair of lever-like memberspivotally connected to the adjacent side of said side housings on theoperator side of said processing rolls, said lever-like membersoperating like bell crank levers having one of their arms extendingdownwardly .in a generally vertical direction and the other of theirarms extending in a general horizontal direction toward said processingrolls, a member extending between said lever-like members and connectedthereto below their pivotal connections with said side housings, meanslimiting movement of said lever-like members about their pivotalconnections with said side housings, means biasing the assembly of saidlever-like members and said member connected therebetween in thedirection to move said member away from said processing rolls, andelectric switches having manual resets connected to said side housingsfor actuation by movement of said assembly in a direction opposite toits biased direction to interrupt said drive means and quickly stoprotation of said processing rolls.

3. In a mill for processing plastic material having a frameincludingspaced side housing in which a pair of processing rolls are supportedfor rotation about axes positioned generally horizontal with referenceto one another, power actuated drive means for rotating said processingrolls, and means for quickly stopping rotation of the processing rollsupon interruption of said drive means, a pair of bell crank leverspivotally connected to the adjacent side of said side housings on theoperator side of said processing rolls with one of their arms extendingdownwardly in a generally vertical direction and the other of their armsextending in a generally horizontal direction toward said processingrolls, abar-like member extending between said bell crank levers andconnected thereto adjacent to the lower ends of the downwardly extendingarms thereof, means limiting movement of said bell crank levers abouttheir pivotal connections with said side housings, means biasing theassembly of said bell crank levers and said bar-like member connectedtherebetween in the direction to move said member away from saidprocessing rolls, and means actuated by movement of said assembly in adirection opposite to its biased direction for interrupting said drivemeans and quickly stopping rotation of said processing rolls.

4. Safety stop apparatus for a mill used to process plastic material andhaving a frame including spaced side housing. in which a pair ofprocessing rolls are supported for rotation about axes positionedgenerally horizontal with reference to, one another, power actuateddrive means for rotating said processing rolls, and means for quicklystopping rotation of the processing rolls upon interruption of saiddrive means, a pair of lever-like members adaptedto be pivotallyconnected to the adjacent" side of the side housings of the mill on theoperator side of the processing rolls, said lever-like members beingadapted to operate like bell crank levers with one of their armsextending downwardly in a generally vertical direction and the other oftheir arms extending in a general horizontal direction toward theprocessing rolls, a member extending between said lever-like members andconnected thereto below their pivotal connections, means 5 limitingmovement of said lever-like members about their pivotal connections,means biasing the assembly of said lever-like members and said memberconnected therebe- 404,624 tween in a first direction to move sald:rnember away 844 349 from the processing rolls, and means actuated bymove- 5 1 447105 ment of said assembly in a direction opposite to said2686930 one direction for interrupting the drive means for the mill andquickly stopping rotation of the processing rolls.

Holmes. Hale.

Thropp. Norton.

WILLIAM J. STEPHENSON, Primary Examiner.

